Hi Bernhard,
Thanks very much for quick reply. I am dealing with suspension flow (particles present in liquid media) and i prepared my solver by editing simpleFoam solver. I think my case and set up is OK, because when i give good initial guess for velocity (by running my case with another solver which is having only one liquid phase), the case is running very well and the results are accurate.
But when i run directly for suspension fluid with out giving good initial guess, i got the above mentioned error. Could you please tell me how to fix this problem.

My first guess would be, that somewhere in your own model, you divide by derivatives of velocities (strain rate or something). Without a good initialization, these derivatives are zero, causing the FPE. Of course when initializing with a real solution for the velocity field, these derivatives will be non-zero.

You have three options.
1. Start from a solved velocity field as initial guess. This is a perfectly fine approach.
2. Adopt your solve, such the flow field gets solved once, before the first iteration.
3. Where you divide by the strain rate, at a very small number. 1/1e-20 is fine, while 1/0 is not.

Hi Bernhard,
In my solver i have already added a small non-local term(a small constant) to local shear rate. Actually there are two models which gives the flow Physics of suspension fluid. For the model-1 your approach is working fine, but for model-2 it is not working. Even though the good initial guess in velocity has no effect.
Should i add anything to .bashrc to ignore such operation (divide by zero).

Adjusting your .bashrc will certainly not be a solution to everything.

You should give more details on the models to see how the problem can be solved. You can easily find out which line is giving you the error (if not by the error itself, then by the infamous 'Info << "Foo 1" << endl;')